Learn about the comparison between traditional and modern systems of shrimp culture.
In traditional system of culture, natural stocking was done through intake of tidal water which carried large numbers of shrimp larvae. These ponds were simple in design and were meant to serve largely as trap ponds. Shrimp larvae were also released directly into the rearing or production ponds by the farmers.
In modern culture necessary ponds have been incorporated for growing larvae to an advanced juvenile stage and later transferred to production ponds. Subsequently, with the adoption of controlled propagation, many shrimp farmers introduced hatchery units also.
Specialisation in culture has also been achieved through rearing of post- larvae or juveniles for sale to farmers, for grow-out culture. Such nursery farms have incorporated brood ponds along with hatcheries and nurseries, and also facilities for growing natural (live) larval food.
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Farmers adopting semi-intensive systems of culture have earthen nursery and rearing ponds with connected dykes. Various types of shelters and artificial substrates have been added to the water in ponds, such as water plants, hollow bricks, plastic hollow pipes, styrofoam sheets, framed nets, etc.
As shrimps formed only a small percentage of the harvest, the tranditional shrimp culture was necessarily a polyculture system where there was inability to control the composition of the seed stock. It is for certain that the species combinations were not always compatable.
Also, the culture procedures were not favourable for high survival rates for shrimps, as the shallow depths of milkfish culture did not permit high stocking rates of shrimp.
Thus, to overcome such difficulties, modern system envisages to adopt monoculture practices. Even combinations with other shrimp species is not advisable in view of the differences in environmental requirements between species. Furthermore, intensive systems of culture of prawn and shrimps are in practice in tank farms.
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In these tanks water is frequently exchanged to maintain high oxygen level as well as to remove metabolic wastes. In case of water crisis, when water exchange is low, heavy aeration is done to keep the organic metabolites in suspension, as these suspended particles serve as biological filters (the dense colonies of nitrifying bacteria grow on them).
The traditional system of paddy-cum-shrimp culture practised mainly on the west coast of India. In such cultures after harvesting of shrimp, the fields are stocked with carp during the rainy season when the salinity in the field is low.